I'm having trouble solving the equation m2 - n2 = 707, where n and m are natural numbers. Because there are 2 variables, even though they are discrete, the obvious thing to do would be to use another equation to solve for one of the variables and then insert the new form to the original equation. The problem is that I don't have another equation to insert anything into. I guess I'm supposed to use the fact that m and n are natural numbers as a hint, but looking at their properties on Wikipedia didn't provide any insight into the subject. Any help would be appreciated.